salukikev
Mechanical
- May 14, 2008
- 110
Hi,
So I had an idea recently while working on a client's project that was inspired by a plug in air freshener. (See here). I've worked on some thermal heating projects before and used PTC's, Tube heaters, Cartridge heaters, and foil heaters. The thing about this project is that we only need a few degrees of warming heat. 25 watts would be about right. Heating approximately 6oz of fluid inside an aluminum reservoir. Shooting for about 10-20 deg F over room temperature in 5 minutes or so, and none of those numbers are particularly critical at this point. I thought I might take a page from the SC Johnson playbook and use a nice cheap 4k power resistor but now I'm wondering what UL will think of that. In the freshener application its the only component- goes right to line voltage and just warms the scented oil. I'm all for keeping it simple, but can I get away with that too? Plan B is use of a PTC but its hard to find one with that low of a power rating. Of course it will add to the expense but the self-regulating feature and UL Cert would likely be worth the cost. So if I can find one that tops out at 30-35c I'll probably be happy.
Just wanted to see if anyone else has gone down this route and what their experience has been. The other thing is if it turns out it IS easy to integrate a power resistor, I could use two of different values and then have a cheap/simple Low/Med/High circuit.
Thanks for any help!
-k
So I had an idea recently while working on a client's project that was inspired by a plug in air freshener. (See here). I've worked on some thermal heating projects before and used PTC's, Tube heaters, Cartridge heaters, and foil heaters. The thing about this project is that we only need a few degrees of warming heat. 25 watts would be about right. Heating approximately 6oz of fluid inside an aluminum reservoir. Shooting for about 10-20 deg F over room temperature in 5 minutes or so, and none of those numbers are particularly critical at this point. I thought I might take a page from the SC Johnson playbook and use a nice cheap 4k power resistor but now I'm wondering what UL will think of that. In the freshener application its the only component- goes right to line voltage and just warms the scented oil. I'm all for keeping it simple, but can I get away with that too? Plan B is use of a PTC but its hard to find one with that low of a power rating. Of course it will add to the expense but the self-regulating feature and UL Cert would likely be worth the cost. So if I can find one that tops out at 30-35c I'll probably be happy.
Just wanted to see if anyone else has gone down this route and what their experience has been. The other thing is if it turns out it IS easy to integrate a power resistor, I could use two of different values and then have a cheap/simple Low/Med/High circuit.
Thanks for any help!
-k
Still, my question is more regarding UL/Costs. The less I have to deal with UL the better, so I want to make sure this will be as painless as possible if I use a power resistor(s) for heating.